Froth flotation is a mineral processing technique for either concentrating a valuable mineral or removing an unwanted mineral. Its chief advantage lies in the fact that it is a relatively efficient process operating at substantially lower costs than many other mineral beneficiation processes.
In general terms, flotation begins with the addition of a collector chemical to a mineral slurry in a process called conditioning. Conditioning is a high shear blending of the collector chemical throughout typical high solids mineral slurry (typical 70% by weight). Properly chosen, the collector chemical coats the surface of some minerals with a greater affinity than others. Once conditioned, the mineral slurry is then diluted (typical 35% solids), and a frothing chemical is added. The frother chemical increases the surface tension (bubble strength) of air bubbles in solution. The slurry is then introduced into flotation cells. Air is introduced and dispersed throughout the slurry. As the individual air bubbles travel to the surface of the flotation cells, they selectively attach to the collector chemical and associated mineral. The froth formed at the surface of the flotation cell is quickly removed, effectively removing a selective mineral captured within the froth.
In purifying industrial sand, the assignee has historically ordered a custom blend chemical with the collectors and frothers premixed. A common term for describing this premixed chemical is to call it a “Promoter Chemical”. The promoter chemical has typically been a combination of four components as follows: (1) Tall Oil/Fatty Acid (TOFA) with a 2%-15% rosin acid content, (2) Petroleum sulfonate; natural and synthetic, (3) Polypropylene glycol monobutyl ether frother, and (4) nonphenol a coupling agent. Petroleum sulfonate, nonphenol and glycol chemicals have become “issues of concern” from a groundwater regulation standpoint. TOFA is an organic product (C18 group) and is a byproduct of the paper industry produced by concentrating the fluid in a distillation process. The rosin content is directly contributed by pine trees and varies with the specification of TOFA and may be varied in the distillation process. The lower the content of rosin, the higher the price.
Thus, the need arises to discover a new promoter chemical that is effective in removing carbonate impurities from industrial sand, while resulting in less negative impact on the environment.